(a) Field of the Invention
The present invention relates to a liquid crystal display and a panel therefor, and in particular, to a four color liquid crystal display.
(b) Description of Related Art
Generally, a liquid crystal display (LCD) includes a liquid crystal panel assembly including two panels provided with two kinds of field generating electrodes such as pixel electrodes and a common electrode and a liquid crystal layer with dielectric anisotropy interposed therebetween. The variation of the voltage difference between the field generating electrodes, i.e., the variation in the strength of an electric field generated by the electrodes changes the transmittance of the light passing through the LCD, and thus desired images are obtained by controlling the voltage difference between the electrodes.
The LCD includes a plurality of pixels with pixel electrodes and red (R), green (G) and blue (B) color filters. The pixels are driven to perform display operation by way of the signals applied thereto through display signal lines. The signal lines include gate lines (or scanning signal lines) for carrying the scanning signals, and data lines for carrying data signals. Each pixel has a thin film transistor (TFT) connected to one of the gate lines and one of the data lines to control the data signals applied to the pixel electrode.
The usual LCD representing one dot by the three RGB colors pixels involves poor optical efficiency. Specifically, the color filters for the respective RGB pixels transmit only one thirds of the light incident thereupon, and hence, the total optical efficiency is deteriorated.
Meanwhile, there are several types of arrangement of the red (R), green (G) and blue (B) color filters. Examples are a stripe type where the color filters of the same color are arranged in the same pixel columns, a mosaic type where the red, green and blue color filters are arranged in turn along the row and column directions, and a delta type where the pixels are arranged zigzag in the column direction and the red, green and blue color filters are arranged in turn. The delta type correctly represents a circle or a diagonal line.
The ClairVoyante Laboratories has proposed a pixel arrangement called the “PenTile Matrix™,” which is advantageous in displaying high resolution images while gives minimized design cost. In such a pixel arrangement, the unit pixel of blue is common to two dots, and the neighboring blue pixels receive the data signals from one data driving IC while being driven by two different gate driving ICs. With the use of the PenTile Matrix pixel structure, the resolution of the ultra extended graphics array (UXGA) level can be realized by way of a display device of the super video graphics array (SVGA) level. Furthermore, the number of low-cost gate driving ICs is increased, but the number of high-cost data driving ICs is decreased. This minimizes the production cost for the display device.
However, with the PenTile Matrix pixel structure, as the size of the blue pixel is different from the size of the red and the green pixels, it is required to make alteration of the storage capacity due to the difference in the liquid crystal charge rate. Furthermore, as two blue pixels are driven by way of one line, the pixel polarities are non-uniformly made.
Particularly, as the blue pixels are arranged in the shape of a stripe, the vertical line patterns due to the blue pixels become easily visible with the insufficient resolution, and this deteriorates the total image quality.